895 research outputs found

    Enhanced Flocculation using Drinking Water Treatment Plant Sedimentation Residual Solids

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    Inefficient removal of total organic carbon (TOC) leads to the formation of carcinogenic disinfection by-products (DBPs) when a disinfectant is added. This study is performed in an effort to develop a simple, non-invasive, and cost-effective technology that will effectively lower organic precursors by having water utilities reuse their treatment residual solids. Jar tests are used to simulate drinking water treatment processes with coagulants-aluminum sulfate (alum), poly-aluminum chloride (PACl), and ferric chloride and their residual solids. Ten coagulant-to-residual (C/R) ratios are tested with water from the Missouri River at Coopers Landing in Columbia, MO versus alluvial ground waters. This treatment results in heavier floc formation and leads to improved sedimentation of organics and additional removal of aluminum and iron. An average of 21%, 28%, and 33% additional TOC removal can be achieved with C/R ratios \u3c 1 with alum, PACl, and ferric chloride, respectively

    The development of a competency assessment standard for general practitioners in China

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    This paper describes the development of a competency assessment standard for General Practitioners in Shenzhen, China. The standard is to be used for developing and delivering the training curriculum for General Practitioners and to enable rigorous assessment of the mastery of the standards by GP trainees. The requirement for the training of General Practitioners in China is mandated by government policy requires an international standard curriculum to meet the needs of patients and the community. A modified Delphi process was employed to arrive at a curriculum consensus. An expert panel and 14 expert working groups derived from the expert panel were established to review and evaluate national and international competency standards for General Practice and develop a set of standards, through a modified Delphi methodology. Forty three experts were involved in the project. The project resulted in a detailed curriculum statement. The curriculum was then used in 2017 and 2018 where pilot examinations of GP trainees (n = 298 and n = 315, respectively) were conducted to assess the trainee's competencies against the Standards. The examination included two modules, a written test (Module A) and a practical test (Module B). The success rate for participants was relatively low with the majority not successfully completing the assessments. The assessments will be further refined in subsequent work. The project achieved its goal of developing a rigorously evaluated standard to support clinical practice and the training and assessment of GPs. © Copyright © 2020 Rao, Lai, Wu, Li, Xu, Browning and Thomas

    Traffic Scheduling Strategy of Power Communication Network Based on SDN

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    Due to the complicated structure, power communication network is difficult to guarantee the quality of service (QoS) of power services. A two-level scheduling algorithm based on software defined network (SDN) is proposed in this paper. Firstly, the priority-based scheduling method is used to meet the latency-sensitive of power service. Then, in order to alleviate congestion, queue bandwidth is adjusted according to network state information, which can be collected by the centralized control of SDN. Finally, the Mininet and Ryu controller are made use of building simulation environment. The test results show that the algorithm proposed in this paper reduce delay and packet loss rate significantly, which achieves QoS

    Intra-Annual Radial Growth of Pinus kesiya var. langbianensis Is Mainly Controlled by Moisture Availability in the Ailao Mountains, Southwestern China

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    Intra-annual monitoring of tree growth dynamics is increasingly applied to disentangle growth-change relationships with local climate conditions. However, such studies are still very limited in subtropical regions which show a wide variety of climate regimes. We monitored stem radius variations (SRV) of Pinus kesiya var. langbianensis (Szemao pine) over five years (2012–2015 and 2017) in the subtropical monsoon mountain climate of the Ailao Mountains, Yunnan Province, southwest China. On average, the stem radial growth of Szemao pine started in early March and ended in early October, and the highest growth rates occurred during May to June. Stem radius increments were synchronous with precipitation events, while tree water deficit corresponded to the drought periods. Correlation analysis and linear mixed-effects models revealed that precipitation and relative humidity are the most important limiting factors of stem radial increments, whereas air temperature and vapor pressure deficit significantly affected tree water balance and may play an important role in determining the growing season length and seasonality (i.e., duration, start, and cessation). This study reveals that moisture availability plays a major role for tree growth of P. kesiya var langbianensis in the Ailao Mountains, southwest China

    Genomic Inference of the Metabolism and Evolution of the Archaeal Phylum Aigarchaeota

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    Microbes of the phylum Aigarchaeota are widely distributed in geothermal environments, but their physiological and ecological roles are poorly understood. Here we analyze six Aigarchaeota metagenomic bins from two circumneutral hot springs in Tengchong, China, to reveal that they are either strict or facultative anaerobes, and most are chemolithotrophs that can perform sulfide oxidation. Applying comparative genomics to the Thaumarchaeota and Aigarchaeota, we find that they both originated from thermal habitats, sharing 1154 genes with their common ancestor. Horizontal gene transfer played a crucial role in shaping genetic diversity of Aigarchaeota and led to functional partitioning and ecological divergence among sympatric microbes, as several key functional innovations were endowed by Bacteria, including dissimilatory sulfite reduction and possibly carbon monoxide oxidation. Our study expands our knowledge of the possible ecological roles of the Aigarchaeota and clarifies their evolutionary relationship to their sister lineage Thaumarchaeota

    Insights into the Ecological Roles and Evolution of Methyl-Coenzyme M Reductase-Containing Hot Spring Archaea

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    Several recent studies have shown the presence of genes for the key enzyme associated with archaeal methane/alkane metabolism, methyl-coenzyme M reductase (Mcr), in metagenome-assembled genomes (MAGs) divergent to existing archaeal lineages. Here, we study the mcr-containing archaeal MAGs from several hot springs, which reveal further expansion in the diversity of archaeal organisms performing methane/alkane metabolism. Significantly, an MAG basal to organisms from the phylum Thaumarchaeota that contains mcr genes, but not those for ammonia oxidation or aerobic metabolism, is identified. Together, our phylogenetic analyses and ancestral state reconstructions suggest a mostly vertical evolution of mcrABG genes among methanogens and methanotrophs, along with frequent horizontal gene transfer of mcr genes between alkanotrophs. Analysis of all mcr-containing archaeal MAGs/genomes suggests a hydrothermal origin for these microorganisms based on optimal growth temperature predictions. These results also suggest methane/alkane oxidation or methanogenesis at high temperature likely existed in a common archaeal ancestor

    Green as the new Lean:how to use Lean practices as a catalyst to greening your supply chain

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    The aim of this research paper is to explore and evaluate previous work focussing on the relationship and links between Lean and Green supply chain management practices. Several explanatory frameworks are explored and discussed. It is intended that evidence and insights can be developed and used: (a) to assist our understanding of where Lean practices are synergistic for Green; (b) to clarify if Green practices are synergistic for Lean; and (c) to identify opportunities for companies to use their Lean framework as a catalyst to making their processes Green. The paper provides evidence suggesting that Lean is beneficial for Green practices and the implementation of Green practices in turn also has a positive influence on existing Lean business practices

    Dysconnection in schizophrenia: from abnormal synaptic plasticity to failures of self-monitoring

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    Over the last 2 decades, a large number of neurophysiological and neuroimaging studies of patients with schizophrenia have furnished in vivo evidence for dysconnectivity, ie, abnormal functional integration of brain processes. While the evidence for dysconnectivity in schizophrenia is strong, its etiology, pathophysiological mechanisms, and significance for clinical symptoms are unclear. First, dysconnectivity could result from aberrant wiring of connections during development, from aberrant synaptic plasticity, or from both. Second, it is not clear how schizophrenic symptoms can be understood mechanistically as a consequence of dysconnectivity. Third, if dysconnectivity is the primary pathophysiology, and not just an epiphenomenon, then it should provide a mechanistic explanation for known empirical facts about schizophrenia. This article addresses these 3 issues in the framework of the dysconnection hypothesis. This theory postulates that the core pathology in schizophrenia resides in aberrant N-methyl-D-aspartate receptor (NMDAR)–mediated synaptic plasticity due to abnormal regulation of NMDARs by neuromodulatory transmitters like dopamine, serotonin, or acetylcholine. We argue that this neurobiological mechanism can explain failures of self-monitoring, leading to a mechanistic explanation for first-rank symptoms as pathognomonic features of schizophrenia, and may provide a basis for future diagnostic classifications with physiologically defined patient subgroups. Finally, we test the explanatory power of our theory against a list of empirical facts about schizophrenia

    Decavanadate effects in biological systems

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    Vanadium biological studies often disregarded the formation of decameric vanadate species known to interact, in vitro, with high-affinity with many proteins such as myosin and sarcoplasmic reticulum calcium pump and also to inhibit these biochemical systems involved in energy transduction. Moreover, very few in vivo animal studies involving vanadium consider the contribution of decavanadate to vanadium biological effects. Recently, it has been shown that an acute exposure to decavanadate but not to other vanadate oligomers induced oxidative stress and a different fate in vanadium intracellular accumulation. Several markers of oxidative stress analyzed on hepatic and cardiac tissue were monitored after in vivo effect of an acute exposure (12, 24 h and 7 days), to a sub-lethal concentration (5 mM; 1 mg/kg) of two vanadium solutions (‘‘metavanadate’’ and ‘‘decavanadate’’). It was observed that ‘‘decavanadate’’ promote different effects than other vanadate oligomers in catalase activity, glutathione content, lipid peroxidation, mitochondrial superoxide anion production and vanadium accumulation, whereas both solutions seem to equally depress reactive oxygen species (ROS) production as well as total intracellular reducing power. Vanadium is accumulated in mitochondria in particular when ‘‘decavanadate’’ is administered. These recent findings, that are now summarized, point out the decameric vanadate species contributions to in vivo and in vitro effects induced by vanadium in biological systems
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